This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: DMSP biosynthesis, dimethylsulfoniopropionate biosynthesis III (algae)
|Superclasses:||Biosynthesis → Other Biosynthesis → Organic Solutes Biosynthesis → Dimethylsulfoniopropanoate Biosynthesis|
Biological degradation of DMSP is the main source for dimethyl sulfide (DMS) in the marine environment [Yoch02] (see dimethylsulfoniopropanoate degradation I (cleavage)). The degradation of DMSP to DMS and subsequent exchange of DMS across the ocean-atmosphere boundary is the main natural source of sulfur to the atmosphere. The flux of DMS from the ocean to the atmosphere is estimated at about 1.5 x 10(13) g of sulfur annually. Once in the atmosphere, DMS plays a major part in cloud formation and potentially in climate regulation.
About This Pathway
Initial studies performed with the green macroalga Ulva lactuca showed that L-methionine was the source of the sulfur atom and both methyl groups in DMSP, and that the α carbon of methionine was the source of the carboxyl group [Greene62, Kahn64]. However, the exact sequence of reactions was not determined until much later, when the pathway for DMSP biosynthesis in the related alga Ulva intestinalis was confirmed by in vivo isotope labelling [Gage97].
Starting from methionine, the pathway includes transamination, reduction, and S-methylation (in this order) producing the novel sulfonium compound dimethylsulfonio-2-hydroxybutanoate, which is oxidatively decarboxylated to DMSP.
As of 2008, none of the enzymes that participate in this pathway has been characterized.
Gage97: Gage DA, Rhodes D, Nolte KD, Hicks WA, Leustek T, Cooper AJ, Hanson AD (1997). "A new route for synthesis of dimethylsulphoniopropionate in marine algae." Nature 387(6636);891-4. PMID: 9202120
Howard06: Howard EC, Henriksen JR, Buchan A, Reisch CR, Burgmann H, Welsh R, Ye W, Gonzalez JM, Mace K, Joye SB, Kiene RP, Whitman WB, Moran MA (2006). "Bacterial taxa that limit sulfur flux from the ocean." Science 314(5799);649-52. PMID: 17068264
Berger03: Berger BJ, English S, Chan G, Knodel MH (2003). "Methionine regeneration and aminotransferases in Bacillus subtilis, Bacillus cereus, and Bacillus anthracis." J Bacteriol 185(8);2418-31. PMID: 12670965
Dolzan04: Dolzan M, Johansson K, Roig-Zamboni V, Campanacci V, Tegoni M, Schneider G, Cambillau C (2004). "Crystal structure and reactivity of YbdL from Escherichia coli identify a methionine aminotransferase function." FEBS Lett 571(1-3);141-6. PMID: 15280032
Heilbronn99: Heilbronn J, Wilson J, Berger BJ (1999). "Tyrosine aminotransferase catalyzes the final step of methionine recycling in Klebsiella pneumoniae." J Bacteriol 1999;181(6);1739-47. PMID: 10074065
Schuster06: Schuster J, Knill T, Reichelt M, Gershenzon J, Binder S (2006). "Branched-chain aminotransferase4 is part of the chain elongation pathway in the biosynthesis of methionine-derived glucosinolates in Arabidopsis." Plant Cell 18(10);2664-79. PMID: 17056707
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